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931  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: LCD and Enclosure. on: June 24, 2009, 04:05:27 pm
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What trouble are you having getting it to work?  It's working for me, but I had to modify the time delays in the arduino liquidcystal library (the problem was with the library, not the display).  I had a horribly frustrating time where it would work once in a while, but 95% of the time would never initialize.

I would get either blank or sometimes the black character boxes showing (I now know) that it was getting power. This was the first LCD module I bought and I had not yet learned about the liquidcrystal library so i was working just from the datasheet. The problem could have been my wiring or my code.  I have it out now and I'll try it again.  What timing did you have to change?

In terms of centering, I just don't believe I could detect the offset, maybe mine is not quite the same.  How are you going to make the cutout for the LCD and attach it?
932  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: LCD and Enclosure. on: June 24, 2009, 01:25:37 pm
to get an idea of what's available, try the pactec web site.http://www.pactecenclosures.com/

They have a wide range of boxes and provide free samples.

I'm working with a similar sized LCD but it's going behind a panel rather than in a box.  I am lucky that I can make my own cutout and fit the LCD into it.  I'm not real sure how I'm going to protect the LCD though - it will be exposed to the elements.

Regardless of research or advice though I would suggest you get your hands on any remotely-possible container and trial fit your stuff.  I never cease to be amazed at how different realitly is from my vague imaginings of what will fit.

oh, by the way, I have one of the Seeed modules in my hand and I would say the LCD face is pretty well centered on the board. It's not EXACT but no more than a couple of mm further from the backlight end of the board than the connector end.

oh, also, I wasn't able to get the Seeed module working myself.  That doesn't mean it won't work for you but I moved on.  If you do get it working I'd like to know.
933  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Arduino boot loader for other Atml on: August 29, 2009, 07:58:26 pm
there's a treatise on the arduino.cc site about bootloaders - have you looked there?
934  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Simple Electronics Question on: August 23, 2009, 04:17:35 pm
The arduino will pretty much act as a 5v source up to the 40ma limit.  A 1K resistor will allow 5ma etc.

I'll be honest though, I'm not real sure how that helps with your transistor question.  Maybe ask again or google "transistor arduino" or variants of that.
935  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Lost values, again. on: August 19, 2009, 12:35:39 pm
yes, software serial should work if you need to use PC serial at the same time as arduino-arduino.

Also, maybe think back to where you started having problems that made you think there was something wrong and whether the PC serial was connected.  If so, try disconnecting it in that instance and see if you can get back on track to where you were originally going. 
936  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Lost values, again. on: August 17, 2009, 09:34:42 pm
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i don't think I saw any code running through the serial monitor at all when the 5v's where not connected.

I don't think connecting the supplies would have any big obvious effect, it's just bad practice..

I do think hooking up rx/tx between two arduinos won't work if one of them has pc serial running since it would be using the same pins.  
937  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Lost values, again. on: August 15, 2009, 12:24:51 pm
also, I don't think it's related but don't connect their 5V rails (unless one is powering the other).

could you describe exactly your wiring and computer hookup?  How do you know what you're sending and receiving?  Could the PC connection be interfering with the arduino-arduino link?

To simplify things, try sending steady spaces or 'A's or whatever to see what you get.
938  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Decoupling with polarized (tantalum) 0.1uF on: August 17, 2009, 09:25:42 pm
I was planning to use tantalum caps(.1 uf and 2.2 uf) on my L4931 power supply because they're physically smaller than the equivalent electrolytics - bad idea?
939  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: digital pins don't always work properly on: August 15, 2009, 08:39:40 pm
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I had a SPDT switch, 5v on the pole, ground on one side and pin 2 on the other.

So you could connect 5v to ground or 5v to pin 2?  I don't see either of those hurting the chip.  I would have a darned good look at the solder and traces around pins 6&7 (pins 12 & 13 on the AVR chip itself).

Putting your chip into a known good board should tell the tale.  They're not expensive if you need to replace it.
940  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: digital pins don't always work properly on: August 15, 2009, 04:05:42 pm
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The Specifications for the ATmega controller chip used on Arduino boards warn not to draw more than 40ma from a pin. They are not protected from over-current and you can damage the pins if you short them out.

The way I read it he had shorted +V, a pin, and ground.  It wouldn't seem the arduino could source much current with the +V shorted to ground.

I guess your point is though that it is possible to damage individual pins without borking the whole device.
941  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: digital pins don't always work properly on: August 15, 2009, 12:18:10 pm
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So I was wiring up a switch to enable the user to choose if he's plugging 4 or 8 lights and I probably shorted something. I had connected the +5v, digitalPin 2 and the ground to my switch but forgot to put a tie down resistor. So when I switched it, my computer gave me a warning that the usb port was drawing too much power.
As described that could draw too much power but i don't see it hurting the arduino.
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But now, the leds connected to digitalPin 11 and 12 are dimmed. It's not the leds as they work on other pins.
...I commented serialPrints and they started working properly. But now I'm having trouble with pins 6 and 7, yet 5 works. I'm not sure if they worked before as I had nothing connected before. I'm currently trying it out with the blink sketch (changing ledPin to 7, 6 and 5) so I'd be very surprised if it was a problem with the sketch. I also have nothing else connected or touchubg the board at the moment. Mind you, this time pin 6 and 7 are not dimmed, they just don't work at all.

Is there something special about pin 6 and 7 that I'm missing out on ? I don't mind connecting to say pin 5 and 4 but it seams I'm getting reliability issues here.
So this has moved around a lot.
What kind of board is it, did you buy it assembled or as a kit and which pins work/dont?

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After some pocking around with the multimeter, turns out when either pin 6 or 7 is on, both out .7v and when they are off they still output .2v, contrarily to the stable 0 of the other pins.
This sounds specifically like a hardware short of both pins to something but the whole business of pins 11 & 12 and the serial don't fit with that.
942  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: 12V & LED's on: July 30, 2009, 03:48:28 pm
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I connected 3 LED's in series to a 12V car battery. The LED's are rated 3.5V 4V max. The question is when the car is running the alternator is sending 14.5 so I was wondering about burning the LED's. Should I install a resistor in the circuit? What value should it be?

For sure you would need a resistor, you can figure out the value from the LEDs current consumption assuming you want to drop 4 volts across it - if the LED's want 40ma then you need like 100 ohms.

I would not be inclined to do this myself though.  I'm not sure how minor differences in the LEDs would affect the result.  There are "12 volt" LEDS meant for automotive use that don't need any coddling - could you try one of those instead?
943  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Serial Monitor VS Serial Output on: July 07, 2009, 03:52:58 pm
what IS the RS232 monitor and does it have any options?
944  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Serial Monitor VS Serial Output on: July 07, 2009, 12:06:05 pm
and is it expecting TTL levels vs RS232?
945  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Burning the bootloader with an Arduino? on: July 29, 2009, 10:34:21 am
don't get hung up on it. try one without the bootloaders and see if you run into any grief.  You still have a bunch of hills to climb to get your project going.
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